The Model IWH instantaneous water heater electric boiler is designed to operate in hot water heating systems with a minimum footprint. It delivers maximum kilowatts and provides instantaneous water heating without a storage tank. A typical Cleaver-Brooks Model IWH hot water boiler system includes operating controls, elements, fuses, contactors, relief valve, drain valve, etc. Vessel sizes range from 6" to 10" diameter with an output spanning 15 kW to 360 kW.